Floating tank roof



Oct. 21, 1952 J 1- w ggms v 2,614,717

FLOATING TANK ROOF Filed April 28, 1950 FIG. 2.

INVENTOR,

JOHN Hf/IGGINS BY M ATTORNEY Patented Oct. 21, 1952 2,614,717 FLOATING TANK noon JohnH. Wiggins, omso, Ill. Application- April 28, 1950, serial No. 158,631

Claims. (01. 220-26) Thisinvention relates to floating tank roofs, and has for one of its'objects to-provide an inexpensive, non-sinkable roof of novel design that is capable of successfully carrying or supportin a very large rain-or snow load. i

Anotherobject is to provide a floating roof, which, inaddition to comprising aperipheral pontoon and a flexible annularfdeck portion attached to said pontoon andsloping downwardly from same towards the center of the tank, is also provided with a central portion of suchdesign v and construction that when a rain or snow load is imposed on thereof, a considerable portion'of the weight of 'saidload will be confined to or concentrated on said central portion and utilized as a weight to further deflect the inner edge of said annular deck portion, and thus enhance the drainage characteristics of said an nular deck portion. I

And still another object of my invention is to provide a floating tank -roof of the kind above referred to, whose central portion is constructed so as to form, in effect, an open container composed ofa stiff, annular rim attached at its lower end to the inner edge of said annular deck portion, and a bottom suspendedfrom said rim at a :point above or higher thanithe point oi attachment of said rim to said annular deokpor-i tion. Other objects and desirable features of my invention will be hereinafterpointedout.

Figure l of the drawings is a vertical, trans-- verse-sectional view of a liquid storage tank pro-- vided with a floating roof embodying my pres'ent invention; and

Figure 2 is a fragmentary, vertical-sectional view, illustrating another form of my invention wherein the only means used to permit rain water to escape from the central deck portion of the roof consists of one or more valve controlled overflow pipes that lead from the central portion of the deck and discharge onto the annular portion of the deck.v

Referring to the drawings, the reference character l designates as an entirety a tank that is adapted to hold liquid. My improved floating roof is composed of or comprises a peripheral pontoon A, preferably constructed in the form of a stiff, annular pontoon provided with internal bulk heads and a weather cover, and attached to a flexible or limber, annular deck portion B that slopes downwardly from said pontoon towards the center of the tank. The central portion of the roof preferably comprises a flexible or limber deck portion C suspended from a stifi, annular rim D, whose lower end is atportion of the Weight'of said load is confined to tached to the inner edge of the annular deck portion B, the weight of said deck portion-C and rim D being suff cient to depress the inner edge of the annular-deck portion B intotli'e -liquid, and thus maintain said deck portion B in a' downwardly-sloped condition; "Preferably,- the central deck portion C has outer edge-attached to the rimD at a point above or higher than the" point of attachment of the lower. end o'f'saidriin to the annular deck" portion B. In effect, the

annular rim D and the central-deck portion C co-act with each other to form an open r ecp tacle that is adapted to conflneor concentrate a rain load on the central portion trtneToof, and thus create an additionalweight;endowmward force, that further depresses the inneedge of the annular deck portion B, 'andhence, 'en-' hances the drainage characteristics of said deck portion B. In other words, my improved roof'is of such construction that when a rain load or snow load is imposed on same, a considerable the central portion of the roof, thereby increasing theweight of said central-portion and-caus ing it to further deflect or exerta downward thrust on the'dow'nwardly-pitched, annm'ar deck portion B that liesbetween the-peripheral pentoo'n'A and the central portion of the roof; I

Various means maybe used to drain the roof. In the form of my invention shownin Fig. 1, the

i'ainnular deck portion Bis provided witli'one oi more hose drains 2 depending from same at points adjacent the rim D and extending laterallythrough the sidewall of the tank-l,"and the central deck portion C is provided "at approximately its center with a depending hose drain 3 which also extends laterally through the side wall of the tank, said drains coaeting with each other to carry off rain water that falls onto the two separate deck portions B and C of the roof. In Fig. 2 of the drawing I have illustrated another form of my invention which differs from the form shown .in Fig. 1 in that the previously mentioned hose drain 3 from the central deck portion C is omitted and means are provided for discharging water from the central deck portion C onto the annular'deck portion B and for enabling a predetermined rain load to be confined on the central deck C if so desired. In this second form of my invention the deck portion B is provided with one or more depending hose drains 2 that extend laterally through the tank side wall, and the sole outlet for rain water that falls onto the central deck portion C consists of one or more horizontally disposed overflow pipes 4 mounted in the annular rim D at a point above and in close proximity to the deck portion C as shown in Fig. 2, and arranged so as to discharge onto the annular deck portion B, each of said overflow pipes 4 being equipped with a check valve 5 arranged so that Water can pass automatically from the central deck portion onto the annular deck portion but no water can return from the annular deck portion B to the central deck portion C throughsaid overflow pipes. In order that a predetermined rain load may normally be confined on the central deck portion C, or in order that the operator in charge of the apparatus may control the passage of rain water from the central deck portion to the annular deck portion B, each of the overflow pipes 4 is preferably equipped with a manually operated.

control valve 6 as shown in Fig. 2.

Elevating the outer edge of the central deck portion C, or attaching said deck portion to the rim D at a pointhigher than the point at which the annular deck portion B is attached to said rim, depresses the rim D, and thus causes the deck' portion B to take a downward slope towards the rim D, which gives excellent drainage to the deck portion B. In addition, water can be allowed to collect on the central deck portion C, both for the purpose of increasing the slope of the annular deck portion B, and for keeping the central portion of the roof cool.

In a floating roof of the kind above described, the central deck portion C will usually constitute a small proportion of the total area'of the roof; for example, about 25%, and it can be made cheaply of heavier than normal plate, say, for example, inch plate, or inch plate, instead of the standardinch plate, of which the peripheral pontoon A and annular deck portion B are normally constructed. Thus, a cheap corrosion allowance is possible to take care of the condition of Water standing on the central portion C of the roof. It is desirable, however, that the top cover of the peripheral pontoon A and the surfaces of the annular deck portion B be effectively drained after each rain, so that the paint thereon will not be ruined and corrosion started. By constructing the roof in the manner above described, I exposeonly a relatively small part (the central portion C) to probably high corrosion, but the corrosion allowance is very inexpensive. If it is desired to normally keep the central portion C of the roof dry, said central portion can be provided with one or more drains, which, at all times are in an open condition as shown in Figure 1. However, as previously stated and as shown in Figure 2, the roof can be constructed in such a way that a Water load can be carried on the central deck portion C and still provide for the escape of water from the peripheral deck portion B through the drains 2 leading therefrom.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A floating tank roof, comprising an annular peripheral pontoon of stiff construction, an annular, flexible deck portion attached at its outer edge to said peripheral pontoon and sloping inwardly from same, a still, annular-shaped rim attached to and projecting upwardly from the inner edge of said annular deck portion, and a central deck portion attached at its outer edge to said annular-shaped rim in a plane higher than the point of attachment of said annular deck portion to said rim, said central deck portion and rim being of suflicient weightto depress the inneredg of said annular deck portion into the buoyant liquid'and maintain said deck portion in a downwardly-sloped condition.

2. A floating tank roof of the kind'described in claim 1, in which said central deck portion is also flexible.

3. A floating tank roof of the kind described in claim 1, provided with a drain leading from said annular deck portion and means for permitting water to pass from said central deck portion onto said annular deck portion.

4. A floating tank roof of the kind described REFERENCES CITED The following references are of record in'the file of this patent: v

UNITED STATES PATENTS Number Name Date 2,017,821 Shanor Oct. 15, 1935 2,497,047 Prager Feb. 7, 1950 2,538,032 Orr Jan. 16, 1951 

